Most scientists consider that changes to the Earth’s climate are caused by increasing amounts of greenhouse gases released by humans from, for example, the combustion of fossil fuels. Carbon dioxide plays a major role in this process.
The oceans absorb carbon dioxide
Approximately half of the emission of carbon dioxide from human combustion of fossil fuels was absorbed by the oceans up until 1994. As the amount of carbon dioxide in the oceans rises, however, their capacity to absorb the gas falls, and it remains in the atmosphere.
“The greenhouse gases raise the temperature of the Earth and this increase is particularly noticeable in the Arctic. It is even more pronounced in Siberia and its coastal seas,” says Iréne Wåhlström, researcher in marine chemistry.
The increase in temperature has an impact on the environment in the Arctic – the cover of sea ice is lower, for example, and the supply of water from rivers increases, the permafrost thaws and the rate of coastal erosion increases.
“One consequence is that organic matter that has been stored in soil is carried to the seas, where it is partially broken down to carbon dioxide,” says Iréne Wåhlström.
Climate change affects the carbon dioxide system
Iréne Wåhlström has investigated two of the coastal seas off Siberia, the Laptev Sea and the East Siberian Sea, in a ship-borne expedition, and – in the case of the Laptev Sea – by mathematical modelling.
The East Siberian Sea has a western part and an eastern part, into which water flows from the Pacific Ocean.
“The level of marine photosynthesis is high in these waters during the summer, and carbon dioxide is consumed. This leads to the level in the sea being lower than in the air, and the sea absorbs carbon dioxide from the air,” says Iréne Wåhlström.
The western East Siberian Sea receives also a major contribution from rivers, both directly from the land and from the neighbouring Laptev Sea.
“The river water contains high levels of organic matter, which is partially broken down to carbon dioxide in the sea. This leads to the level in the sea being higher than in the air, and thus carbon dioxide flows from the sea into the air, accelerating climate change.”
The Laptev Sea had an excess of carbon dioxide during the late summer of 2008 that was of the same order of magnitude as the western East Siberian Sea, probably caused by the breakdown of organic matter from the land.The results suggest that the Laptev Sea has changed from being a sink for atmospheric carbon dioxide to become a source of carbon dioxide during the late summer. This will probably be reinforced by a higher air temperature, particularly if parts of the large reservoir of stored organic matter in the Arctic tundra thaw and are carried to the sea. This will further increase the rate of temperature rise of the Earth.
Rapid plankton growth in ocean seen as sign of carbon dioxide loading
27.11.2015 | Johns Hopkins University
Revealing glacier flow with animated satellite images
26.11.2015 | European Geosciences Union
Planet Earth experienced a global climate shift in the late 1980s on an unprecedented scale, fuelled by anthropogenic warming and a volcanic eruption, according to new research published this week.
Scientists say that a major step change, or ‘regime shift’, in the Earth’s biophysical systems, from the upper atmosphere to the depths of the ocean and from...
The Fraunhofer Institute for Solar Energy Systems ISE has installed 70 photovoltaic modules on the outer façade of one of its lab buildings. The modules were...
Nerve cells cover their high energy demand with glucose and lactate. Scientists of the University of Zurich now provide new support for this. They show for the first time in the intact mouse brain evidence for an exchange of lactate between different brain cells. With this study they were able to confirm a 20-year old hypothesis.
In comparison to other organs, the human brain has the highest energy requirements. The supply of energy for nerve cells and the particular role of lactic acid...
In laser material processing, the simulation of processes has made great strides over the past few years. Today, the software can predict relatively well what will happen on the workpiece. Unfortunately, it is also highly complex and requires a lot of computing time. Thanks to clever simplification, experts from Fraunhofer ILT are now able to offer the first-ever simulation software that calculates processes in real time and also runs on tablet computers and smartphones. The fast software enables users to do without expensive experiments and to find optimum process parameters even more effectively.
Before now, the reliable simulation of laser processes was a job for experts. Armed with sophisticated software packages and after many hours on computer...
Researchers at Heidelberg University have devised a new way to study the phenomenon of magnetism. Using ultracold atoms at near absolute zero, they prepared a...
25.11.2015 | Event News
17.11.2015 | Event News
21.10.2015 | Event News
27.11.2015 | Press release
27.11.2015 | Life Sciences
27.11.2015 | Materials Sciences